Fuelled by a £1 million boom in sex toys and accessories (including official 50 Shades-branded items), 61% of Britons claim they are "open to the idea" of having a sex contract with their partner.

An online store that specialises in personalised gifts says searches for sex contracts — where partners promise each other to dress up in maid outfits or have sex in places other than the bedroom — have increased by 320% since the trailer for the forthercoming film of the book came out.

A commissioned survey asking 2,132 British adults who had been in a relationship for over a year revealed that not only were almost two thirds open to the idea of having a sex contract, a further 18% has already introduced one into their lives.

The subjects who said they would consider or already own a sex contract were asked about the appeal of having one — 42% thought it would spice up their love life, with another 33% keen to try something new.

STEAMY: Searches for buying sex contracts online have spiked with the release of the 50 Shades film trailer [PH]

“It certainly seems as though the British public are looking to introduce some kinkiness to their boudoirs”

Mike Herbert, of gonedigging.co.uk

If there was any doubt that Fifty Shades of Grey is the inspiration for these newfound kinksters, 67% confirmed that they had been inspired by the books or movie trailer.

They were also interested in getting their friends into some naughty fun, with 79% of those in sex contracts recommending having one and over half claiming their sex lives have improved as a result.

Mike Herbert, of gonedigging.co.uk, said: "We were shocked to see the impact of the 50 Shades trailer to our online searches. It certainly seems as though the British public are looking to introduce some kinkiness to their boudoirs and our range of sex contracts has never been so popular!"

He predicts that the novelty item will definitely have another popularity spike on Valentine's Day next year when Fifty Shades of Grey is released in cinemas starring pop singer Rita Ora and Once Upon a Time's Jamie Dornan.